1. Field
Embodiments of the invention relate to laminated articles and layered articles and more particularly to low alkali glass laminated articles and layered articles useful for, for example, electrochromic devices.
2. Technical Background
The management of natural light is a consideration in architectural design, for example, how to maximize the view of the outside while ensuring that the interior of the building is comfortable for the occupants. For example, too much light can increase the heat and/or brightness inside the building. Windows which can be switched from transparent to varying degrees of tinted and back to transparent, for example, electrochromic windows, are being developed to minimize one or more disadvantages associated with increased glass usage, for example, heat gain and glare.
Windows for use, for example, in automobiles and in architecture must meet several safety codes and are subject to mechanical strength tests, for example, debris impact tests and post-breakage wind cycling. Windows can benefit from increased mechanical strength, for example, in order to withstand environmental conditions.
Functional materials for electrochromic, photochromic, thermochromic, and low-e type applications are typically applied to a thick soda lime glass substrate, which is laminated to a second thick soda lime glass substrate in order to meet the above mentioned safety codes. The substrates are often coated with a barrier layer in order to minimize alkali, for example, sodium diffusion from the substrate into the functional materials. However, any breaks in the barrier layer, for example, scratches can allow sodium or alkalis to enter the functional material, compromising the utility of the functional material. Defects in the soda lime glass, for example, bubbles, scratches, inclusions can also compromise the utility of the functional material.
Glass strength can depend on exposure temperatures, aspect ratio, plate size, stiffness and load duration. Laminated glass can be made with annealed, heat strengthened, and/or fully tempered for additional benefits, such as resistance to increased wind loading, increased impact resistance or resistance to thermal stress.
It would be advantageous to have laminated articles and layered articles in which alkali diffusion such as sodium diffusion can be minimized and where mechanical strength and/or clarity can be maximized.